Conducting polymers reflectance spectroscopy

H.J. Lee and S.M. Park, Electrochemistry of conductive polymers. 33. Electrical and optical properties of electrochemically deposited poly(3-methylthiophene) films employing current-sen-sing atomic force microscopy and reflectance spectroscopy. J. Phys. Chem. B, 108,16365 (2004). 

Over recent years, internal reflectance infrared studies have tended to concentrate on the study of relatively thick films of conducting polymers or layers, (see, for example, the work of Pham and coworkers [49, 50], or Kvarn-strom, Nauer, Neugebauer and coworkers [51-54]) in which sensitivity was not a particular problem, or on the semiconductor-electrolyte interface, (see the work of Chazalviel and coworkers [35, 40, 41]), in which the SPP excitation approach is not appropriate. However, interest has focused again on this phenomenon with the surface-enhanced infrared absorption spectroscopy (SEIRAS) studies of Osawa and coworkers [19, 26, 27, 46, 55, 56], who have combined the application of the Kretschmann configuration with step-scan FTIR spectroscopy to study fast, reversible electrochemical processes on timescales down to microseconds [26, 46, 57-60]. 

Reflectance spectroscopy is commonplace for samples that cannot be prepared for transmittance measurements. However, reflectance measurements must be carefully conducted as the reflected beam is not only indicative of the composition of the sample but is also affected by surface conditions at the sample plane. This makes the reflectance spectra, though indicative of material chemistry, difficult to interpret and generally less useful for quantitative analysis. Since the polarization of the beam is maintained for reflectance, especially specular reflectance methods, examination of orientation at polymer surfaces using reflection techniques is attractive [10]. Reflection-absorption modes involve the transmission of the infrared beam through the sample and subsequent reflection to pass through the sample again. Usually, sample preparation is difficult for such experiments and they... 

These examples demonstrate the interest of conducting polymers as matrices to disperse active electrocatalysts, so that a detailed investigation of their electroformation and of the catalyst incorporation process was undertaken at the molecular level, using in situ" U V-visible Reflectance Spectroscopy (UVERS). 

A neural stimulation system typically uses constant current to deliver charges required to excite cells or neurons however, this often causes voltage excursion to exceed 1 V on the stimulation electrode. In comparison, impedance spectroscopy traditionally operates in the 5-50 mV range, typically 10 mV, without dc bias for simplicity in data interpretation [34, 109]. However, the small potential without dc bias does not accurately reflect the performance at high potentials that are involved in oxidation or reduction reactions for conducting polymers. In fact, electrode... 

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